Radiant-energy-transmission system



oct 16, 192s. 1,688,036

L. M. CLEMENT RADIANT ENERGY TRANSMISSION SIST Filed Aug. 5, 1924 afm? aan,

'/nyen/or.- eW/LsMC/emenf Patented O'ct. 16, 1928.

UNITED STATES PATENT oFFICE.

RADIANT-ENERGY-TRANSMISSION SYSTEM.

Application med August 5, 1924. semi No. 730,159.

essary. This problem presents itself, for ex' ample, in connection With the installation of radio receiving systems in apartment houses and on battleships. In these instances, 1t becomes desirable to be able to transmit waves received by a common receiving antenna to` a plurality of radio receiving stations located in different apartments inthe one case or at a central point in the battleship in the other case. The present invention affords a solution of the problem by the provision of means for coupling an antenna to receiving stations at a distance therefrom which efficiently transmits high frequency waves. t

An object of this invention is totransmit high frequency waves Without substantial attenuation.

Another object is to couple an antenna to receiving, devices by means having low 1mpedance. p

An additional object is to distribute high frequency Waves to a plurality of receiving stations without substantial attenuation.

Another object is to transform the voltage* of high frequency Waves to allow their transmission without substantial loss of power.

A feature of the invention relates to means for coupling an antenna to radio receiving devices that have low impedance to `high frequency Waves. p

This invention provides means for the transmission of high frequency waves, for example, between an antenna and receiving sets. -It includes means for transforming the voltage of high frequency waves at each end of a conducting line. To reduce the leakage effect of line capacity in producing attenuation of high frequency Waves, the voltage of Waves supplied to the input end of the line is stepped down to a low value. The wave energy is thus transmitted over the line at low voltage and, at the output end of the lof different signaling line, the voltage of the transmitted energy may bestepped up before it is supplied to the recelvlng devices. As a consequence, the

attenuation of the high frequency waves is greatly reduced.

radio receiving lsystems wherein 1t may be desirable to 4transmit received radio frequency waves from an antenna to one or more receiving devices at a distance therefrom. In some instances, a plurality of high frequency waves, representing carrier waves in different signaling channels may be transmitted via a single coupling line, such as has been described above, to a plurality of selectlve receiving devices. In other instances, individual coupling lines may be provided for separately transmitting the carrier waves channels. Desired waves may be selected and undesired waves excluded from the receivingdevices in an case by the use of properly designed filters, placed either at the antenna or at the receiving stations or at both points. The voltage of the transmitted waves may be transformed This invention is particularly applicable toby'means of transformers, 'amplifiers or like devices.

In the drawings* y Fig. l-is a circuit diagram of a radio receiving system in Which an antenna 10 is coupled to a plurality of radio receiving vsets .2, and R3 byah-igh frequency coupling line 16.

Fig. 2 is a circuit diagram in which resista-nce coupling to the antenna and receiving devices is employed.

Fig. 3' is a circuit diagram illustrating a balanced coupling to an antenna and counterpoise,

Fig. 4.- is a circuit diagram of a multiplex radio receiving system provided with filters both at the antenna and at the receiving devices. i

Fig. 5 is a circuit diagram of aA multiplex receiving system having an individual coupling line for each receiving device.

The radio receiving system, the circuit diagram of which is shown in F ig, 1, comprises antenna 10, which may be an open type, loop type, or other form of antenna, a wave secoupling system 15 and individual receiving sets, R1, R2 and R3. The antenna 10 is connected to ground in series with the primary winding of transformer 12. The secondary winding of transformer 12 is connected to the inpu:J terminals of band filter 11. The output end of this band filter is coupled to the low impedance line 16 by step-down radio frequency transformer 13. At its output end, the line 16 is coupled to radio receivers R1, R2 and R3 by step-up transformers 17 18 and 19 in multiple. The transformer 13, the line 16 and the transformers 17 18 and 19 constitute the coupling system 15. Radio receivers R1, R2 andR3 are connected respectively to the secondary windinfs of transformers 17 18 and 19.

LThe radio frequency band filter 11Aisclesigned to transmit, without substantialattenuation, waves of frequencies which it is desired to receive and to greatly attenuate waves of undesired frequencies. ,The .stepdown transformer 13 is designed to transmit high frequency waves and to reduce the voltage of those waves applied to the coupling line 16. 17, 18 and 19 are designed to transmit radio frequency waves and to'step-up the voltage of those waves. The transformers 17, 18 and 19 may be replaced by space discharge tube amplifiers or other devices for transforming the voltage of received Waves. The secondary winding of transformer 13, the line 16, and the primary windings of transformers 17, 18 and 19 preferably have low impedance.

In the operation of the system of Fig. 1, high frequency waves,.corresponding to signals, are received by antenna 10 and transmitted through transformer 12 to band filter 11. Filter 11 selectively transmits desired waves and attenuates undesired waves. The voltage of high frequency waves received by antenna 1() is stepped down by means of transformer 13. The high frequency waves are thus transmitted over line 16 at low voltage. These waves are stepped up in voltage at transformers 17 18 and 19, and then applied to the respective radio re- For high frequency waves, the capacity component of the impedance of transmission line 16 predominates over other components of this impedance for any appreciable length of the line. By reducing the voltage of the high frequency waves applied to thetransmisson line 16, the effect ofthe Capacity component impedance of the line in producing attenuation of these waves is materially reduced. The current transmitted is proportional to the applied voltage but the loss in energy caused by attenuation 1s pro-y portional to the square of the voltage. It

ltherefore results that by reducing the voltage of the waves to be transmitted by one- Conversely, the transformers secondary windings.

-poise vcei'vers R1, R2, and R3,

the loss of energy caused half, for example,

be reduced to one-fourth by attenuation may of its former value.

In Fig. 2, a circuit diagram of a radio receiving system is illustrated. In this figure, the antenna 10 is connected to ground in series with the resistance 14. The radio frequency band filter 11 has its input terminals connected to the terminals of resistance 14. The output terminals of band filter 11 are connected to resistance 2O which is connected in shunt to primary winding of transformer 13. The resistances 14 and 20 serve to prevent reaction between the filter 11,y and the antenna 10 and the line 16. These resistances are preferably designed to match the filter input and output impedances respectively.

.connected to the low impedance line 16. The

output terminalsof line 16 are connected to the radio receivers R1, and R2.

The respective branches of line 16, connected to receivers R,L and R2, contain resistances 21 and 22. These resistances are provided to prevent mutual reaction between the receivers R1 and R2. They, in effect, loosen the coupling between the receivers and allow either to be tuned without effect upon the tuning of the other.

In Fig. 3, a modification ,of the antenna 10 of the radio receiving .system illustrated in Fig. 1 is shown. This modification, which may be substituted for the portion of Fig. 1 to the left of line 3-3, includes antenna 10 connected to one terminal of inductance 23 and counterpoise 10 connected to the opposite terminal of this inductance. The midpoint of inductance 23 is connected to ground. The input terminals 0f band filter 11 are connected to adjustable contacts on inductance 23. The inductance 23 is preferably adjusted to match the impedance of the filter, 11. A transformer 13', the primary -wind'zng of which is connected to the output terminals of band filter 11, has a ground connection at the mid-point of its primary and This modification provides a balanced circuit for use'when a counterpoise is employed. This arrangement-venables the effective potential of the counter- 10 with respect to ground to be maintained the same as the effective potential of the antenna to ground.

In the system illustrated in, Fig. 4, band filters are provided both at the antenna. end and at the receiver end of the low impedance transmission line 16.y Three receiving channels associatedrespectively with radio reeach include a band filter BFl, BF2, and BF3, respectively. In

this figure, the step-down and step-up trans-l form the necessary voltage transformation.

The system shown in Fig. 4 is particularly suitable for multi leX radio reception. The band filter 11 is designed to transmit Waves within the band of frequencies including the carrier waves corresponding to the receiving channels 1, 2 and 3. The band filters BF1, BF2, and BF3 are each designed to selectively transmit the carrier wave corresponding to the associated channel.

The band filters BF 1, BF2, and BFS, being located at the receiving sets, have the additional function of discriminating between desired waves and extraneous waves picked up by transmission line 16.

The circuit diagram of Fig. 5 is that of a multiplex radio receiving system wherein individual Coupling lines are provided for separate receiving channels. The output terminals of band filter' 1l are connected in multiple to the input terminals of individual channel band filters BF', BF and BF". The output terminals of the latter filters are connected to the coupling systems 25, 26 and 27, respectively. Additional band filters BFI, BF2, and BF3 are provided at the receiver ends of the coupling systems for dis criminating between desired Waves and extraneous energy picked up by the coupling lines. These filters also supplement the band filters BF', BF and BF in selecting the carrier wave corresponding to the associated channel and attenuating waves corre sponding to other channels. The system shown in this figure combines high efficiency in the transmission of radio frequencies with high selectivity in the discrimination between desired and undesired waves. This modification is especially suited for use where the radio receivers R R2 and R3 are located at widely separated points.

For the purposes of explanation, this invention has lbeen illustrated and described in connection with certain specific embodiments, but it is to be limited only by the scope of the appended claims.

What is claimed is:

l. An electric wave transmission system comprising an antenna, a radio apparatus at a distance from said antenna, a line having normally high attenuation connected between said antenna and said radio apparatus and means including a step-down transformer connected to said line for enabling the transmission of high frequency waves without substantial attenuation.

2. A radio receiving system comprisingk an antenna, a radio receiver, and means for coupllng sald recelver to sald antenna comprising a two winding step-down transformer, a two winding step-up transformer and a line connecting the secondary of said step-down transformer to the primary of said step-up transformer, said means ,being designed to efficiently transmit high frequency waves.

3. A radio receiving system which comprises an antenna, a lurality of radio receivers, and means or coupling said receivers to said antenna comprising a two winding step-down transformer, a plurality of two winding step-up transformers and a line connecting the secondar of said stepdown transformer to the prlmaries of said step-up transformers, said means being designed to efliciently transmit high frequency waves.

4. A radio receiving system which com-v prises an antenna, a plurality of sets of signal receiving apparatus, and means for selectively transmitting high frequency waves between said antenna and said sets of a paratus without substantial attenuation wlilch comprises a filter, and a low impedance line a d a step-down transformer coupling said fi ter to said line.

5. A radio receiving system which comprises an antenna, a plurality of sets of radio receiving apparatus, a single low impedance coupling line for said antenna and receiving apparatus designed to reduce the attenuation of high frequency waves trans- -mitted thereover, and means for preventing mutual lreaction of each of said sets upon the others.

6. In a radio receiving system an antenna, a count-erpoise, a common ground connection for said antenna and counterpoise, a band filter, means for coupling said filter to said antenna and counterpoise in a balanced arrangement, said means having an impedance which `is adjustable to match the input impedance of said filter, a low impedance coupling system and a plurality of radio receiving devices, said coupling system being arranged in energy transfer relation between said filter and said devices.

7. In a radio receiving system an antenna, a plurality of radio receivers, and individual low impedance coupling lines between said antenna and said receivers comprising step down transformers for transforming the voltage of waves transmitted over said lines to a low value.

In witness whereof, I hereunto subscribe my name this 28th day of July A. D., 1924:.A

LEWIS M. CLEMENT. 

